This invention relates to noise and vibration reduction in computer disk drives.
In typical disk drive assemblies; a major source of acoustic noise is sympathetic vibration of the disk drive housing caused by the spindle motor used to spin the disks or by the actuator used to move the read/write heads across the disks for data access. The disk drive assemblies are commonly in the form of a rectangular housing with a spindle motor and actuator motor mounted to one internal surface of the housing. A plate is used to cover the housing and motors. In many assemblies the shaft of the spindle motor is attached to the base plate. Therefore the housing vibrates at resonant frequencies, increasing the total amount of acoustic noise. With high performance requirements expected to increase to rotational speeds greater than 30,000 rotations per minute (rpm), noise and vibrations have become an even greater engineering concern.
Vibrations of the plate are typically caused by the bending and torsion modes associated with the plate. Approaches to reducing noise and vibration include providing an isolation device between the motors and the housing. Another approach is to provide damping (constraint) layers. The foregoing approaches to reducing noise and vibration are directed toward eliminating or reducing the torsion and bending modes of the entire plate. Improvements for reducing the vibrations and noise of the entire plate are desirable, particularly for high rotational speeds.
A disk drive assembly can include a housing having regions of a polymeric material. The polymeric regions can include openings substantially filled with a polymeric material such as a liquid crystal polymer. The polymeric regions, which may form a uniform pattern, can be formed in various parts of the housing, including the base plate or the cover, and can help reduce noise and vibrations that occur during operation of the disk drive.
In one aspect, a disk drive assembly includes a housing having openings substantially filled with a polymeric material. Various components can be disposed within the housing including a read/write head assembly, an actuator motor to control positioning of the read/write head assembly, a recording medium, and a spindle motor to control rotation of a recording medium.
A method of manufacturing a disk drive assembly also is disclosed and includes forming a housing having a pattern of holes, substantially filling the holes with a polymeric material, and mounting internal components of the disk drive assembly within the housing. A mold injection or other technique can be used to substantially fill the openings with the polymeric material.
One or more of the following advantages may be present in various implementations. By reducing the affects of noise and/or vibrations during operation, the disk drive can be operated at higher speeds. Furthermore, the techniques described here can be used in conjunction with or instead of constrain layers. When used instead of such constraint layers, the current techniques can be used without increasing the thickness of the base plate. That can be important for certain applications, such as mobile disk drives, in which the disk drive must operate within strict Z-height limitations. Moreover, the disclosed techniques do not require an additional assembly step during manufacturing.
Other features and advantages of the invention will be apparent from the detailed description, the accompanying drawings and the claims.